Various cleaning articles have been created for dusting and light cleaning. For example, cloth rags and paper towels used dry or wetted with polishing and cleaning compositions have been used on relatively flat surfaces such as countertops, showers, sinks and floors. Laminiferous wipes have been proposed, as disclosed in U.S. Pat. No. 9,296,176. But, rags, wipes, and paper towels are problematic for reasons such as hygiene (the user's hands may touch chemicals, dirt or the surface during cleaning), reach (it may be difficult to insert the user's hand with the rag, wipe or paper towel into hard-to-reach places) and inconvenience (cleaning between closely-spaced articles typically requires moving the articles).
To overcome the problems associated with using rags and paper towels, various reusable dust gathering devices using felt and hair have been utilized for more than a century, as illustrated by U.S. Pat. No. 823,725 issued in 1906 to Hayden and using yarns as illustrated in U.S. Pat. No. 4,145,787. To address the problems with reusable dust gathering devices, disposable cleaning articles have been developed which have limited re-usability. These disposable cleaning articles may include synthetic fiber bundles, called tow fibers, attached to a sheet as shown in U.S. Pat. Nos. 6,241,835; 6,329,308; 6,554,937; 6,774,070; 6,813,801; 7,003,856; 7,566,671; 7,712,178; 7,779,502; 7,937,797; 8,146,197; 8,151,402; 8,161,594, 8,186,001; 8,245,349; 8,646,144; 8,528,151; 8,617,685; 8,756,746; 8,763,197; 9,113,768 and 9,198,553.
For cleaning of floors and other hard surfaces, various cleaning sheets have been used in conjunction with various cleaning implements. The sheets are removably attachable to the cleaning implement, which allows the user to remain upright and provides ergonomic convenience. For example, microfiber cleaning pads have been used for wet and dry cleaning of floors and other target surfaces. Microfiber pads may be nylon and are intended to be washed and reused. But microfiber pads may damage the floor and still leave filming/streaking, particularly after repeated washings.
Accordingly, nonwoven cleaning sheets have been used, particularly for cleaning of dry target surfaces. Nonwoven cleaning sheets are typically discarded after a single use, and not laundered or otherwise restored. Nonwoven sheets for cleaning hard surfaces, such as floors, countertops, etc., are known in the art as shown in U.S. Pat. Nos. 3,629,047 and 5,144,729. To provide durability, a continuous filament or network structure has been proposed, as disclosed in U.S. Pat. Nos. 3,494,821; 4,144,370 and 4,808,467 and polymers as described in U.S. Pat. No. 5,525,397. Other attempts include providing a surface which is textured with peaks and valleys for trapping debris as disclosed in commonly assigned U.S. Pat. No. 6,797,357.
Nonwoven sheets having tow fibers have been proposed, as disclosed in U.S. Pat. Nos. 6,143,393; 8,225,453; 8,617,685; 8,752,232; 8,793,832 and in commonly assigned U.S. Pat. No. 8,075,977. Webs with elastic behavior have been proposed in commonly assigned U.S. Pat. No. 5,691,035. Sheets with recesses have also been proposed, as disclosed in U.S. Pat. Nos. 6,245,413; and 7,386,907. Sheets with cavities have been proposed, as disclosed in U.S. Pat. No. 6,550,092. An adhesive cleaning sheet is proposed in U.S. Pat. No. 7,291,359. But these attempts require additional complexity in the manufacture of the nonwoven.
Yet other attempts use coatings of wax and/or oil. Coatings of wax and oil are generally disclosed in U.S. Pat. Nos. 6,550,092; 6,777,064; 6,797,357; 6,936,330; 7,386,907; 7,560,398; 8,435,625; 8,536,074; 9,204,775; 9,339,165 and EP 1482828. Commonly assigned US 2004/1063674 teaches a mineral oil. Specific amphiphilic coatings are disclosed in U.S. Pat. No. 8,851,776. U.S. Pat. No. 8,093,192 teaches partially hydrogenated soy oil, but does not recognize how to use the oil for hard surface cleaning or for processing a cleaning article. Swiffer® Dusters, sold by the instant assignee, have been sold with up to 7 weight percent oil for off-the-floor cleaning.
But even these teachings do not address the proper type of soy oil coatings for a cleaning article. Too little coating is not efficacious. Coating which is sufficient to be efficacious often contaminates production machinery, requiring maintenance and cleaning. Such coating can also leave unsightly residue on the target surface during a cleaning task.
Thus the type of coating should also be considered. Applicant has unexpectedly found that even small variations in processing the coating raw materials can have a significant effect on coating efficacy. Particularly, soy oil has been tried as a raw material for coatings. Soy oil is commercially processed and sold in a hydrogenated or partially hydrogenated form for use. Hydrogenation is the process of adding hydrogen to a substance for the purpose of converting double bonds between an alkene into single bonds, forming alkanes. Hydrogenation generally hardens a coating. Generally harder coatings are easier to process, for manufacturing operation operations such as cutting, folding and stacking of substrates. But hard, solid coatings generally do not perform as well in use as softer, liquid coatings for attracting and retaining dust, lint and particulates on a nonwoven. Coatings are potentially more spreadable, when in a liquid state, increasing collection and retention of debris during cleaning. Thus, one of skill making a coating for a hard surface cleaning article has to face the dilemma of the tradeoff between processability and cleaning efficacy.
Accordingly, this invention addresses the problem of how to incorporate the proper type of soy oil into a coating for a cleaning article without sacrificing cleaning efficacy while providing processability in manufacture. Applicant has unexpectedly found a particular type of soy oil which is decouples the tradeoff between efficacy and processability.